The DUP’s Brexit spokesman Sammy Wilson has said that “no one believes the Prime Minister” over her Brexit promises, but the party would still vote to back Theresa May in the event of a no confidence vote.

Mr Wilson said that, if the deal is voted down on December 11, there would be “no cause to bring the government down on that basis”, but that support would be withdrawn “if the Prime Minister or the government continues to try and pursue the same route set out in this agreement”.

Speaking to Julia Hartley-Brewer on the talkRADIO breakfast show, Mr Wilson reiterated that the DUP do not support Mrs May’s deal.

Legal advice on the agreement from Attorney General Geoffrey Cox was released yesterday, that confirmed it would keep the UK and Northern Ireland in a customs union with the EU, but they would be treated as separate countries for administrative purposes.

'Is it the best deal available?'

An anti-Brexit sign on the Irish border. Image: Getty

“No MP will be happy to go back to their constituents and tell them that if this agreement goes through, you’ll have to regard the rest of the UK as a third country, that you’ll be subject to another administration, i.e. Brussels, dictating over 300 areas of policy in your own constituency with no say over any of those laws now or in the future,” said Mr Wilson.

“No MP would ever tolerate that for their own area yet that is what this agreement was going to impose on Northern Ireland if it goes through.”

“You can see it’s a bad deal, I can see it’s a bad deal, yet the Prime Minister is standing on the floor of the House saying it’s the best deal available. Is it the best deal available?” asked Hartley-Brewer.

“They couldn’t possibly believe the Prime Minister when such a devastating commentary on this agreement has been given by her own legal officer.”

'We should not fear no deal'

If the deal is voted down, he said, Mrs May should return to Brussels and “stand up for Britain”.

Hartley-Brewer asked why, if the DUP’s position was clear, they’d back Mrs May in a vote of no confidence.

“If this deal is defeated next Tuesday, the immediate threat of the break up of the United Kingdom and the damage to Northern Ireland will have been removed, therefore we will have no cause to bring the government down on that basis,” Mr Wilson explained.